How many protons, neutrons, and electrons are there in an atom of chlorine-37?

1. How many protons, neutrons, and electrons are there in an atom of chlorine-37? • Complete the following chart:

2. Atomic Mass Definition & Calculation

3. Weighted average of the atomic masses of the isotopes of an element. • Measured in atomic mass units (amu). • Typically found below an element’s symbol in the periodic table. • Generally is not a whole number. • What is the atomic mass of Lithium? • 6.94 amu • What element has an average atomic mass of 32.07 amu? • Sulfur - S Average Atomic Mass

4. Two isotopes of chlorine occur in nature: chlorine-35 and chlorine-37. Calculate the average atomic mass if 75% of the naturally occurring chlorine is chlorine-35 and 25% is chlorine-37. • Step 1: Multiply each mass number by its percentage abundance over 100. • 35 x = 26.25 • 37 x = 9.25 • Step 2: Add answers from step 1. • 26.25 + 9.25 = 35.5 • Step 3: Interpret answer. • The average atomic mass of chlorine is 35.5 amu. Calculating Average Atomic Mass

5. Two isotopes of boron occur in nature: boron-11, and boron-10. Calculate the average atomic mass if 80% of the naturally occurring boron is boron-11 and 20% is boron-10. • Step 1: Multiply each mass number by its percentage abundance over 100. • 11 x = 8.8 • 10 x = 2 • Step 2: Add answers from step 1. • 8.8 + 2 = 10.8 • Step 3: Interpret answer. • The average atomic mass of boron is 10.8 amu. Calculating Average Atomic Mass